Evaporator



Feb.. 23, 1932. p. B. SADTLER 1,846,067

EVAPORATOR n Filed Feb. 1, 1929 :s sheets-sheet 41 7%39925' Jdffzerf. l,l v4 Feb. 23, 1932. P. B. SADTLER EVAPORATOR Filed Feb. l, 1929 Ziff-QE' 3 Sheets-Sheet 2 lilllllllllllllllilllllll Billlllllllllllllllllllnlullllllllillllllllllll nlllllllllilllllllllllll IIIIIHIHMINIIIIIIIHlIllllllllllNl/Ulll'llllll 'lllllllllllllllllllllllllllllllllllllllllllllllll llllllllllllllllllllllillillllullullllllllllll lllIIlllllHllllhll lll Feb. 23, 1932. P. B,SADTLER 1,846,067

EVAPORATOR Filed Feb. l, 1929 3 Sheet's-Sheet 5 Patented Feb. 23, 1932UNITED STATES PATENT OFFICE PHILIP B. OF HARVEY, VLLINOIS, ASSIGNYOR TSWENSON' EVAPORATOR (7011l PANY, 0l' HARVEY, ILLINOIS, A CORPORATION 0FILLINOIS 'appumio med February 1, 192e. seieny no. ssa'ze.

This invention relates to evaporators and more particularly tothe typeof evaporator known as the horizontal tube eva orator.

This type of evaporator, whic has been known ever since steam heatedevaporators were built, possesses many advantages, especially withrespect to its cheapness of construction and ease ofthe tube renewal,but it has relativelylow heat transfer coefficients. A form which hasbeen widely used has a rectangular body with the tube banks coverinethefull width of the body. Horizontal tu evaporators have also been builtwith the body in the form of a vertical cylinder, the tube banks in suchcases -varying from the fullwidth of the cylindrical portion to a widthless than that of the cylindrical portion. The cylindrical constructionhas cer tain advantages as regards erection and maintenance of joints. lI

It is well known that the rate of heat transfer in evaporators islargely dependent upon the velocity of the circulating liquids. In thehorizontal tube eva orator, vthe circulation of the liquid is caused bybubbles of steam liberated on the heating surface and rising through themass of the liquid. If the cross section of the evaporator is entirelyfilled with tubes, the generation of steam bubbles Vbeing uniform, nodefinite circulationl is set up. In actual practice, the generation ofsteam bubbles is likely to be more `violent at the point where the steamenters and therefore the liquid usually circulates upwardly between thetubes at the steam entrance end and downwardly between the tubes at thesteam exit end. In the case of evaporators having a body in the form ofa vertical cylinder with the tube banks narrower than the diameter ofthe cylinder, zones are formed at the side of the evaporator containingno heating surfaces. The theory in such cases is that the liquid willcirculate upwardly between the tubes and 'downwardly through the 4emptyzones, butin practice this 'does not generally occur, andthecirculation' in such evaporators is similar to that described above forevaporators with a 1rectangular body.'

In order to provide vigorous circulation of the liquid, it is necessarythat the rate of steam evolution be hi hly concentrated in certain areasand that t ere be much less steam evolution, or none at all, in certainother culation will be more vigorous and heat transfer rates will begreater.

It is therefore an object of my invention to provide an evaporator ofincreased capacity and having large heating surfaces per unit of floorspace occupied, with well defined, concentrated heating zones for theupward circulation of the liquid to be evaporated and other well definedzones containing relatively little heatin surface for the downwardcirculation of t e liquid.

It is a further object of this invention to .s

provide an evaporator having a low cost per unit of heating surface.

It is a further important object of this invention to provide a type ofhorizontal tube evaporator wherein two sets, or banks of tubes areemployed, arranged at such an angle with respect to each other that thetubes are readily removable even where a luralltyof evaporator units areplaced in c osely adjacent position with respect to each other.

Other and further important yobjects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.l

This invention (in a preferred form) is illustrated in the drawings andhereinafter more fully described. Y On the drawings:

Figure 1 is a vertical sectional view of an invention, with parts inelevation;

evaporator embodying the principles of my Figure 2 is a sectional viewtaken substan-` tially on line II-II of Fig. 1";'

Figure 3 is a fragmentary sectional view showing a modified manner ofsecuring the tubes in the tube sheets;

Figure 4 is a fragmentary sectional view of a second modified mannerof,securir:g the tubes in the tube sheets; l

Figure 5 isa top plan view of a modified form of my evaporator arrangedin a plurality of evaporating units;

Figure 6 1s an enlarged horizontal sectional view of one of theevaporating units shown in Figure 5;

Figure 7 is a detail view of a plate for securing the tubes, with partsin elevation; and

Figure 8 is a fragmentary sectional view taken substantially on lineVIII-VIII of Fig. 7, with parts in elevation.

The reference numeralA 1 indicates an evaporator embodying theprinciples: of my invention. Said evaporator 1 is preferably 1 -formedin two or more sections, wlth a lower body casting 2 provided with foursteam chambers, 3, 4, 5 and 6.

Said steam chambers may be cast integral with the body casting 2 or castseparately and bolted to the body section by means of bolts 7 as shownin Fig. 3.

In the steam chambers, there are tube sheets 8, 9, 10 and 11,respectively, provided with apertures for the insertion of heating tubes12. These tube sheets may be cast integrally with the body casting 2, asshown in Figures 1 and 2, or they may be cast `integral with the steamchests, as the tube sheet 60 shown in Figure 3; or they may be entirelyseparate vfrom either and be secured to the back of the steam chest byany convenient means as in the case of tube sheet 61 shown in Fig. 4.

The evaporator 1 yincludes in addition to the body casting 2, one ormore body rings 13, a cover 14 having a vapor outlet l5 therein, and abottom 16 havlng a liquidwithdawal connection 17. The liquid to beevaporated may be fed into the evaporator at any convenient point, suchas throughthe opening 18 below the tubes 12.

Between the tube sheets 8 and 9 are posi-l tioned a plurality of tubes12 with their ends secured in said tube sheets 8 and 9, respectively, toform one set, or bank 19. A second set, or bank 20 extends between thesheet tubes 10 and 11 with their respectiife ends secured therein.Ordinarily, the steam banks and their tube sheets will be so placed thatthe tube chests 19 and 20 are at right angles to each other, as shown inFigures 1 to 4 inclusively, but that the angle may be less than a rightangle is illustrated by Figs. 5 and 6. The number of rows of tubes ineach set 19 and 20, respectively, is a matter of"calcula tion for eachindividual case and is determined by methods familiar to those skilledin the art of evaporator design.

Steam, or other vapor used for heating, is'

supplied through a pipe 21 having a branch pipe 22 connected to thesteam chest 4 and e the evaporator body, so that spaces 26 are formedbetween the evaporator body wall and the outer vertical rowsof tubes 12in which there are no tubes at all. This arran ement also leavesportions 27 wherein the tuIies extend in a single direction only. Theremain ing central portion is substantially filled with intersectingrows of tubes forming a large number of vertical passa es 28, aroundwhich the heating surface is hly concentrated and which form fairlyeinite paths for ascending columns of liquid.

The spaces 26 and 27, which are free or relatively free of heatingtubes, form zones in which the evolution of steam is less violent andtherefore serve as passages for accommodating downwardly moving currentsof liquids.

In this way, the requirements for vigorous circulation yin evaporatorsof the horizontal tube type are fulfilled and because of this vigorouscirculation, higher heat transfer coeicients are obtained than inpreviously known types of horizontal tube evaporators.

Where for purposes of design, it becomes necessary tov use relativelylong, small diameter tubes, a support for these tubes at inters mediatepoints is required. Tube supporting plates 29 and 30 serve this purposeand also define the central area in which t e liquid to be evaporated isupwardly circulated.

Because of the violent ebullition and rapid circulation occasioned inthe central area by foregoing construction, it is sometimes advisable toposition a deilecting member 62 (Fig. 1) above saidy central area toprevent entrainment.

It will be understood that instead of arranging the intersecting tubebanks 19 and 20 with alternate single rows, two rows of the tubes in thebank 20 may be inter tween two single rows of tubes in the bank 19, orany other desired arrangement may be effected. Preferably, however,alternate, single rows of intersecting tubes are employed and thesetubes are arranged in as closely adjacent relation to each other as ispracticallv possible.

In Figs. 5 and 6 there is shown an arrangement of evaporator units 30,31 and 32 wherein the steam chests 33, 34, 35 and 36 of each and yet.permit of easy removal of the tubes. As best shown in Fig. (i the tubebanks 3T and 38 forni in this case a diagonally shaped central zone 39wherein the heating' surfaces are closely concentrated and outer zones40 and 41 containing no tubes and tubes running in a single direction,respectively. As before, tube supporting plates 42 and 43 are providedto more definitely confine the centralized heating zone.

In Figures 7 and 8, is illustrated the preterred manner of securing thetubes 12 in a tube sheet 44. Said tube sheet 44 is provided withapertures 45 of larger diameter than the outside diameter of the tubes12, the ends of which extend through said tube sheet 44 as at 4G. Asuitable beveled packing 47 surrounds each of said tube ends 4G and isadapted to be pressed around said tube ends and into the apertures 45,which are countersunk as at 48 for that purpose. A plate 49 having'apertures 50 for receiving the ends ot' tour of the tubes 12 is adaptedto be placed over said tube ends and secured to the tube sheet 44 bymeans of a central bolt and nut 51 and 52 respectively. In this positionthe clamping plate 49 engages the packing 47 and wedges it tightly inposition.

In usual evaporator practice, the plate 49 is positioned with two of itsedges horizontal and the dimensions between centers of the apertures 50are such that the vertical distance between successive tubes or rows oftubes is slightly greater than the outside tube diameter. Consequently,my method of arranging two sets of intersecting tubes practicallydoubles the beating surface for the same space occupied by a single setof tubes such as normally used.

I am aware that many changes may be made and numerous details ot'construction may be varied through a wide range withoutdeparting fromthe principles ot this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art.

I claim as my invention:

1. In a horizontal tube evaporator having a cylindrical body, twointersecting sets of tubes disposed substantially at rightangles to eachother within said body, the width of each set of tubes being less thanthe diameter of the body to form spaces adjacent the body wall free oftubes, spaces adjacent the body wall containing tubes running in onlyone direction and a central space filled with closely adjacent,criss-crossed tubes and tube supporting plates bounding said centralspace to define an area tor the upward circulation of a liquid to beevaporated.

2. In a horizontal tube evaporator having a cylindrical body, twointersecting sets of horizont-ally disposed tubes within said body, cachset comprising a plurality of'closely spaced tubes arranged invertically and horizontally alined rows with the horizontal rows of oneset alternating with the horizontal rows of the other, each of said setsbeing of a width less than the diameter of the body to provide a centralspace substantially iilled with closely arranged intersecting tubes andouter spaces relatively free o tubes, aml baille members bounding saidcentral space to detine an area for the upward circulation ot a liquidto be evaporated.

3. In a horizontal tube evaporator intersecting sets of tubes, tubesupporting plates boundingl the crossed portions of said tubes tothereby form chambers in said evaporator to define the path ot' travelof the liquid to be evaporated.

4. In a horizontal tube evaporator intersecting sets of tubes, the widthof said tube sets being substantially less than the width ot' the bodyso as to form a central space having closely adjacent criss-crossedtubes and other spaces having lesser members 0f tubes. and tubesupporting plates forming bounding walls for said central space.

I n testimony whereof I have hereunto subscribed my name at Chicago,Cook County,

Illinois.

PHILIP SADTLER.

